Lifting-jack.



PATENTED AUG. 14, 1906.

N. x A EJ T TG mm .T MN .L P

APPLICATION FILED MAYS, 1,906.

UNITED STATES PATENT OFFICE.

Specification of Letters Patent.

Patented Aug. 14, 1906.

Application filed May 3, 1906. Seria No. 315,033.

To ail whom it 7nd, concern:

Be it known that I, FRANK M. PATTERSON,

a citizen of the United States, residing at \Vinfield, in the county ofCowley and State 5 of Kansas, have invented certain new and usefulImprovements in Lifting-Jacks; and I do hereby declare the following tobe a full, clear, and exact description of the invention, such as willenable others skilled in the art to which it appertains to make and usethe same, reference being had to the accompany.

ing drawings, and to the letters of reference marked thereon, which forma part of this specification.

This invention relates to new and useful improvements in lifting-jacks;and the object of the invention is to produce a simple and eflicientdevice of this nature in which a longitudinally-movable rack-bar isadapted to be actuated by cog-teeth upon a pivotal lever and so arrangedthat the teeth upon the lever may be thrown out of gear with therack-teeth as the handle is raised to get a new purchase upon therack-bar.

The invention consists, further, in the provision of means in alifting-jack in which a longitudinally-movable rack-bar is providedadapted to be actuated by means of a pivotal lever having rackteethwhich mesh with the teeth of a rack-bar and in the provision of apivotal pawl for holding the rack-bar as it is raised while the ocrating-lever is raised and automatically re eased from the rackbar toget a new purchase upon the teeth thereof.

My invention consists, further, in other details of construction andarrangements of parts, which will be hereinafter fully described andthen specifically defined in the appended claim.

I illustrate my invention in the accompanying drawings, in which Figurel is a side elevation of my improved lifting-jack, and Fig. 2 is asectional view i 5 centrally and longitudinally through the device.

Reference now being had to the details of the drawings by letter, A desinates the standard of my lifting-jack, which is prefer- ;o ably hollow,and mounted within the standard is the longitudinally-movable rack-barB, having teeth B upon one face thereof, and a bracket member B projectsfrom one face of said barand is guided in a slot C in one 5 face of thestandard. Bracket extensions A project from the standard, and each ofsaid bracket-arms has an angled slot A in which the pivot-pin D has aplay.

E designates an operating-handle having a head E with cog-teeth thereon,which are adapted to mesh with the teeth of said rackbar, and said pin Dpasses through the handle of the lever, thereby forming means wherebythe lever may be fulcrumed.

F designates a locking-pawl having pintles Ff projecting from oppositeedges thereof, which pintles are journaled in apertures in the bracketextensions of the standard. One edge of said pawl, which is angular, isadapted to normally engage the teeth of the rack-bar and prevent thesame from movement in one direction. A lug G, projecting from one end ofsaid pawl, rests in a groove N, formed in the edge of thereleasing-plate N, which latter is pivotally mounted upon one of saidpintles F. The lower end of said releasing member N has an angledprojection N forming a convenient means whereby the member may be rockedupon its pivot for the purpose of releasing the pawl from the teeth ofthe rack-bar.

The operation of myinvention is as follows: When it is desired to raisean object, either by bringing the bracket-arm B in contact therewith orwhether the object to be moved rests upon the plate 0 at the top of therackbar, the latter is raised or given a longitudinal movement by thedownward movement of the lever, which causes the ends of the pivotal pinD to fulcrum in the lower ends of the angled slots A which throws theteeth upon the head E of the lever in mesh with the teeth of therack-bar. After the lever has been swung to its-lowest limit the pawlwill hold the purchase, and by raising the lever the cog-teeth upon thehead thereof will be thrown out of mesh with the teeth of the rack-barby reason of the elongated angled slot A thereby allowing the lever tobe raised for a new purchase upon the teeth of the rack-bar. When thelever is raised a suflicient height and it is desired to swing the samedownward, the teeth in the head thereof will readily mesh with. theteeth of the rackbar, and by repeating the swinging movement of thelever the rack-bar may be extended step by step, as may be desired. Asthe lever is swung to its highest position the angled slot will throwthe teeth upon the lever out of engagement with the teeth of therack-bar, and if the pawl is thrown out of en gagement with saidrack-bar the latter will fall by gravity, which will also be the casewhen the lever is at its lowest throw, provided the awl is disengagedfrom the teeth of the rac -bar. By simply pushing upon the lower end ofthe releasing member the awl will be readily disengaged.

While I have shown my invention as ap plied especially to alifting-jack, it will be understood that the principle may be appliedequally as well for various purposes, with slight modifications, toadapt the same for any particular purpose, the essential feature of theinvention being the means whereby the cog-teeth of the lever may beautomatic- ?)lly thrown out of engagement with the rack- What I claimis- A lifting-jack comprising a standard, a longitudinally-movablerack-bar mounted pro ection upon one end of said pawl, a pawlreleasingmember pivotally mounted upon one of said pintles and having a recess tore oeive said projection of the pawl, as set forth.

In testimony whereof I hereunto affix my signature in the presence oftwo witnesses.

FRANK M. PATTERSON. Witnesses:

S. 0. BLACK, GEO. HULVEY.

